1University of Colorado, Department of Geological Sciences, Boulder, CO, USA
2University of Colorado, Community Surface Dynamics Modeling System, INSTAAR, Boulder, CO, USA
3University of Colorado, CIRES, Boulder, CO, USA
4University of Copenhagen, Copenhagen, Denmark
Received: 07 Nov 2013 – Discussion started: 20 Dec 2013
Abstract. The freshwater flux from the Greenland Ice Sheet (GrIS) to the North Atlantic Ocean carries extensive but poorly documented volumes of sediment. We develop a suspended sediment concentration (SSC) retrieval algorithm using a large Greenland specific in situ data set. This algorithm is applied to all cloud-free NASA Moderate Resolution Imaging Spectrometer (MODIS) Terra images from 2000 to 2012 to monitor SSC dynamics at six river plumes in three fjords in southwest Greenland. Melt-season mean plume SSC increased at all but one site, although these trends were primarily not statistically significant. Zones of sediment concentration > 50 mg L−1 expanded in three river plumes, with potential consequences for biological productivity. The high SSC cores of sediment plumes ( > 250 mg L−1 expanded in one-third of study locations. At a regional scale, higher volumes of runoff were associated with higher melt-season mean plume SSC values, but this relationship did not hold for individual rivers. High spatial variability between proximal plumes highlights the complex processes operating in Greenland's glacio–fluvial–fjord systems.
Revised: 09 May 2014 – Accepted: 24 May 2014 – Published: 04 Jul 2014
Hudson, B., Overeem, I., McGrath, D., Syvitski, J. P. M., Mikkelsen, A., and Hasholt, B.: MODIS observed increase in duration and spatial extent of sediment plumes in Greenland fjords, The Cryosphere, 8, 1161-1176, doi:10.5194/tc-8-1161-2014, 2014.